A portable application can be run from a removable drive (USB flash drive, iPod, portable hard drive, etc) on any Windows computer without installation.
You will carry the program with settings on removable drive and don't modify settings on host computer.
On Vista and above turn off User Account Control (UAC) or run launcher as admin.

Extract and run ImageResizerPortable.
You can add switches (App\ImageResizer\switches.txt) with AdditionalParameters in ImageResizerPortable.ini.
Settings of installed ImageResizer should be preserved.

The 4.x online setup fails to properly install the app because the source file it is not avaliable at the source anymore.To solve this, just grab it from archive.org and place alongside the Bernat's installer and everything will be fine and dandy!:)(note the "xx" on the link below and replace it accordingly):